title: Clinical Outcomes in Patients with Heterogeneous Vancomycin-Intermediate Staphylococcus aureus Bloodstream Infection.
abstract: The prevalence of heterogeneous vancomycin-intermediateStaphylococcus aureus(hVISA) infections varies in the literature, a problem complicated by the lack of routine screening procedures; however, limited data suggest that hVISA has been associated with persistent bloodstream infections (BSI) and vancomycin failure, yet these studies have been confounded by design issues. We conducted this study to compare the characteristics of patients with BSI caused by hVISA with those with vancomycin-susceptibleStaphylococcus aureus(VSSA) treated with vancomycin. This retrospective, multicenter matched (1:1) cohort study compared the clinical characteristics and outcomes of hVISA and VSSA. Patients with hVISA methicillin-resistantStaphylococcus aureus(MRSA) BSI from 2004 to 2012 were matched to VSSA-MRSA BSI patients. The primary outcome was failure of vancomycin treatment, defined as a composite of persistent bacteremia (≥7 days), persistent signs and symptoms, change of MRSA antibiotic, recurrent BSI, or MRSA-related mortality. We identified 122 matched cases. The overall vancomycin failure rate was 57% (82% hVISA versus 33% VSSA;P< 0.001). The individual components of failure in hVISA versus VSSA were persistent bacteremia, 59% versus 21% (P< 0.001); change in MRSA therapy, 54% versus 25% (P= 0.001); MRSA-related mortality, 21% versus 10% (P= 0.081); and recurrence of BSI, 26% versus 2% (P< 0.001). Using logistic regression analysis and adjusting for covariates, hVISA (adjusted odds ratio [aOR], 11.1; 95% confidence interval [CI], 4.3 to 28.7) and intensive care unit (ICU) admission (aOR, 4.5; 95% CI, 1.8 to 11.6) were still independently associated with vancomycin failure. Relative to VSSA BSI, patients with hVISA were more likely to experience failure of vancomycin treatment, including persistent bacteremia and recurrence. Our results indicate that hVISA was responsible for considerable morbidity.
authors.affiliation: Anti-Infective Research Laboratory, Pharmacy Practice Department, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, Michigan, USA.
authors.forename: Anthony M
authors.initials: AM
authors.lastname: Casapao
authors.affiliation: Bouvé College of Health Sciences, School of Pharmacy, Northeastern University, Boston, Massachusetts, USA.
authors.forename: Steven N
authors.initials: SN
authors.lastname: Leonard
authors.affiliation: Anti-Infective Research Laboratory, Pharmacy Practice Department, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, Michigan, USA.|Department of Pharmacy Services, Henry Ford Hospital, Detroit, Michigan, USA.
authors.forename: Susan L
authors.initials: SL
authors.lastname: Davis
authors.affiliation: Department of Pharmacy Practice, Albany College of Pharmacy and Health Sciences, Albany, New York, USA.
authors.forename: Thomas P
authors.initials: TP
authors.lastname: Lodise
authors.affiliation: Department of Pharmacy Practice, Albany College of Pharmacy and Health Sciences, Albany, New York, USA.
authors.forename: Nimish
authors.initials: N
authors.lastname: Patel
authors.affiliation: Department of Pharmacy, The Ohio State University Medical Center, Columbus, Ohio, USA.|Pharmacy Practice and Administration, The Ohio State University College of Pharmacy, Columbus, Ohio, USA.
authors.forename: Debra A
authors.initials: DA
authors.lastname: Goff
authors.affiliation: Department of Pharmacy Practice, The University of Rhode Island College of Pharmacy, Kingston, Rhode Island, USA.|Infectious Diseases Research Program, Veterans Affairs Medical Center, Providence, Rhode Island, USA.
authors.forename: Kerry L
authors.initials: KL
authors.lastname: LaPlante
authors.affiliation: Department of Pharmacy and Therapeutics, University of Pittsburgh School of Pharmacy, Pittsburgh, Pennsylvania, USA.|Antibiotic Management Program, University of Pittsburgh Medical Center, Presbyterian University Hospital, Pittsburgh, Pennsylvania, USA.
authors.forename: Brian A
authors.initials: BA
authors.lastname: Potoski
authors.affiliation: Anti-Infective Research Laboratory, Pharmacy Practice Department, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, Michigan, USA m.rybak@wayne.edu.|School of Medicine, Wayne State University, Detroit, Michigan, USA.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Rybak